No abstract

Fletcher and Bloom (1988) have argued that as readers read narratives, clause by clause, they repeatedly focus their attention on the last preceding clause that contains antecedents but no consequences in the text. This strategy allows them to discover a causal path linking the text's opening to its final outcome while minimizing the number of times long-term memory must be searched for missing antecedents or consequences. In order to test this hypothesis, we examined the reading times of 25 subjects for each clause of eight simple narrative texts. The results show that: (1) causal links between clauses that co-occur in short-term memory (as predicted by the strategy) increase the time required to read the second clause; (2) potential causal links between clauses that never co-occur in short-term memory (again as predicted by the strategy) have no effect on reading time; and (3) reinstatement searches are initiated at the end of sentences that are causally unrelated to the contents of short-term memory or that contain clauses that satisfy goals no longer in short-term memory. These results support the claim that subjects engage in a form of causal reasoning when they read simple narrative texts.In the research reported here, we have examined the joint implications of two well-known claims about narrative comprehension. The first of these asserts that comprehension is a problem-solving process, in which the reader must discover a series of causal connections that link a text's opening to its final outcome (Black & Bower, 1980;Schank, 1975;Trabasso & Sperry, 1985;Trabasso & van den Broek, 1985). The second holds that a strategic process focuses a reader's attention on a subset of the information inhis or her short-term memory after each sentence is read, and that comprehension is facilitated if an appropriate connection exists between this information and the sentence that follows (Fletcher, 1981(Fletcher, , 1986Kintsch & van Dijk, 1978;Miller & Kintsch, 1980;van Dijk & Kintsch, 1983). Fletcher and Bloom (1988) have argued that both claims can be correct only if the attentionfocusing process identifies the most likely causal antecedent of the sentence that will follow and if the correct antecedent (or sometimes consequence) is reinstated from long-term memory whenever this process fails.To discover how such a process might work, Fletcher and Bloom (1988) examined a sample of narrative texts and found that the most likely causal antecedent of any This research was supported in part by the Center for Research in Learning, Perception, and Cognition at the University of Minnesota, and by Grants MH42468-DI and AFOSR-86-D280 to Charles R. Fletcher.Portions of the research were presented at the 1987 convention of the Psychonornic Society in Seattle, WA. We are grateful to Alice Healy, Ed O'Brien, Tom Trabasso, and an anonymous reviewer for their comments on an earlier version of this paper. Requests for reprints should be addressed to Charles R. Fletcher, Department of Psychology, University of Minnesota, 75 East River R...

Circadian rhythm disruption is one of the earliest biomarkers of Alzheimer’s disease (AD), and there exists a bidirectional relationship by which dysfunctions in the circadian clock drive AD pathology and AD pathology drives circadian dysfunction. Casein kinase 1 (CK1) isoforms ε and δ, key circadian regulators, are significantly upregulated in AD and may contribute to AD pathogenesis. In the current studies, we have examined how inhibition of CK1ε/δ with PF-670462 (at 10 mg/kg, δ isoform selective, or 30 mg/kg, δ and ε selective) impacts regional Aβ and circadian gene expression in 10–13 month old APP-PS1 mice and nontransgenic controls. We have also assessed circadian, cognitive, and affective behavioral correlates of these neural changes. At baseline, APP-PS1 mice showed a short period, as well as impaired cognitive performance in both prefrontal cortex and hippocampus-dependent tasks. Both doses of PF-670462 lengthened the period and improved affect, whereas only the higher dose improved cognition. Further, PF-670462 treatment produced a dose-dependent reduction in amyloid burden – overall Aβ signal decreased in all three areas; in the prefrontal cortex and hippocampus, PF-670462 also reduced plaque size. Together, these findings support chronotherapy as a potential tool to improve behavior in AD.

A controlled comparison of a human-centered operator interface to that of a traditional distributed control system interface was conducted to establish the human performance improvement. Twenty-one professional petrochemical plant operators completed a series of matching process upset scenarios on their respective plants' high-fidelity training simulators. Each scenario contained an equipment or process failure previously experienced in the real plants. The results indicated that operators using the human-centered design completed scenarios an average of 7.5 minutes faster (41% improvement over the traditional interface), successfully dealt with failures in 96% of the cases (a 26% improvement), and recognized the presence of the failure before the first process alarm in 48% of the cases (a 38% improvement). These performance results were then used as input to a Monte Carlo simulation that estimated the economic benefit for the human-centered interface at $1,090,000 CAD per year for a plant of comparable size.